package dfs_bfs;

public class lc200 {
    public static void main(String[] args) {
        System.out.println(numIslands(new char[][]{{'1','1','0','0','0'},{'1','1','0','0','0'},
                {'0','0','1','0','0'},{'0','0','0','1','1'}}));
    }
    public static int numIslands(char[][] grid) {
        //dfs
        int s = 0;
        int m = grid.length;
        int n = grid[0].length;
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if(grid[i][j] == '1') {
                    dfs(grid, i, j);
                    s++;
                }
            }
        }
        return s;
    }
    public static void dfs(char[][] grid, int i, int j){
        if(i < 0 || i >= grid.length || j < 0 || j >= grid[0].length || grid[i][j] == '0')
            return ;
        grid[i][j] = '0';
        dfs(grid, i + 1, j);
        dfs(grid, i - 1, j);
        dfs(grid, i, j - 1);
        dfs(grid, i, j + 1);

    }
}
